Small nonhuman primates, frequently the common marmoset (calithrix jacchus), are extensively used for biomedical research. Animal research demands an interaction between the animal and research staff, and this often involves capture, retrieval, handling, and transportation. These activities can cause marked changes to measured biological parameters as well as decreases in overall health and well-being of the animal.
Two methods are commonly employed for capture, retrieval, and handling of marmosets. These methods, hand and net capture, raise safety concerns for both animal and handler. Hand capture involves the reach of an individual into the animal's housing cage while wearing thick protective gloves. Such gloves are not typically long enough to cover the entire length of arm protruding into the cage during capture, and while long sleeve garments are indeed available to cover an operator's extended arm in the cage, the potential for any exposure of unprotected skin inside the cage of animals known to have infectious diseases, sharp teeth, and aggressive traits at times is not safe practice. In addition, marmosets typically try to avoid capture by fleeing side to side at the rear or top of the cage or cling tightly to the cage walls. This can cause injuries to themselves or their paired housing mate during removal from their home cage.
Protective gloves, used in both hand and net capture, can inadvertently harm the marmoset. When catching marmosets by hand, the use of heavy, protective gloves (leather gloves or chain-mail gauntlets over leather gloves) has been highly recommended. However, the decrease in tactile sensation for the handler necessitates the weight of the glove used be carefully gauged to ensure that excessive pressure is not applied to the animal, thereby causing injury. The use of heavy, protective gloves to handle marmosets may also result in damage to their teeth if they bite. Prolonged handling with heavy gloves can also cause injury during repositioning of the animal following capture.
Although commonly used, nets for catching marmosets can cause untoward injuries as they engage in typical avoidance responses. A quick sweep of the net at a fleeing marmoset can cause harm from purpura to fracture of long bones (e.g. humerus, femur). The net capture is a frightening and stressful experience which tends to exhaust the marmoset and may result in injury.
Facilities are often recommended to have cages equipped with sliding or false backs, called squeeze-back cages, enabling marmosets to be moved slowly to the front of the cage for administration of medications, injections, and experimental procedures. These cages are easy to use, and effectively immobilize the animal for routine procedures. Squeeze-back cages are not useful for more complicated techniques and can only be used for singly housed marmosets. While safer than hand or net capture, squeeze-back cage capture has been associated with increased cortisol, signs of distress, and decreases in testosterone and serum prolactin in various marmoset species.
Squeeze-back cages are not ideal when they are solely used as the home cage to facilitate restraint and capture because these cages are small, lack enrichment, and perpetuate a constant fear of capture. Another option is for cages to be fitted with a sliding panel in the door to permit the easy transfer of the animal into a transport cage. However, use of sliding panels for smaller transport cages and squeeze-back cages are not universal in all marmoset-research facilities.
The ideal method for gentle capture would be use of a device that minimizes stress, exposure of handler to animal, physical handling and manipulation of the animal, and time to capture. The present invention provides such device.